using System;
using System.IO;
using System.Threading;
using System.Collections.Generic;

public class StreamWriterProxy :
   IDisposable
{
    StreamWriter Writer = null;
    bool bValid = false;

    public StreamWriterProxy(string InFilePath, bool bInCreateNew)
    {
        BackgroundWorker.Instance.AddBackgroudOperation(() => this.Reset_MT(InFilePath, bInCreateNew));
        bValid = true;
    }

    public void Flush()
    {
        BackgroundWorker.Instance.AddBackgroudOperation(() => this.Flush_MT());
    }

    public void Dispose()
    {
        BackgroundWorker.Instance.AddBackgroudOperation(() => this.Dispose_MT());
        bValid = false;
    }

    public void Close()
    {
        BackgroundWorker.Instance.AddBackgroudOperation(() => this.Close_MT());
    }

    public bool isValid
    {
        get
        {
            return bValid;
        }
    }

    public void WriteLine(string InText)
    {
        DebugHelper.Assert(bValid, "Should not WriteLine When the Proxy is not valid!");

        BackgroundWorker.Instance.AddBackgroudOperation(() => this.WriteLine_MT(InText));
    }

    protected void Flush_MT()
    {
        if (Writer != null)
        {
            Writer.Flush();
        }
    }

    protected void Reset_MT(string InFilePath, bool bInCreateNew)
    {
        try
        {
            FileStream fs = null;

            if (bInCreateNew)
            {
                fs = new FileStream(InFilePath, FileMode.Create, FileAccess.Write, FileShare.Read);
            }
            else
            {
                fs = new FileStream(InFilePath, FileMode.Append, FileAccess.Write, FileShare.Read);
            }

            Writer = new StreamWriter(fs);

            bValid = true;
        }
        catch (Exception)
        {
            // lost logs.
#if DEBUG
            //UnityEngine.Debug.Break();
#endif
        }
    }

    protected void Dispose_MT()
    {
        if (Writer != null)
        {
            Writer.Dispose();
        }
    }

    protected void Close_MT()
    {
        if (Writer != null)
        {
            Writer.Close();
        }
    }

    protected void WriteLine_MT(string InText)
    {
        if (Writer != null)
        {
            Writer.WriteLine(InText);
        }
    }
}

public class BackgroundWorker :
    Singleton<BackgroundWorker>
{
    public delegate void BackgroudDelegate();

    Thread WorkingThread = null;
    bool bRequestExit = false;

    List<BackgroudDelegate> PendingWork = new List<BackgroudDelegate>();
    List<BackgroudDelegate> WorkingList = new List<BackgroudDelegate>();

    public int ThreadID = 0;

    public override void Init()
    {
        WorkingThread = new Thread(new ThreadStart(StaticEntry));
        ThreadID = WorkingThread.ManagedThreadId;
        WorkingThread.Start();
    }

    public override void UnInit()
    {
        bRequestExit = true;
        WorkingThread.Join();
        WorkingThread = null;
    }

    protected static void StaticEntry()
    {
        BackgroundWorker.Instance.Entry();
    }

    static void Swap<T>(ref T a, ref T b)
    {
        T t = a;
        a = b;
        b = t;
    }

    protected void Entry()
    {
        while (!bRequestExit)
        {
            {
                lock (PendingWork)
                {
                    Swap(ref PendingWork, ref WorkingList);
                }
            }

            int Count = WorkingList.Count;
            for (int i = 0; i < Count; ++i)
            {
                try
                {
                    WorkingList[i]();
                }
                catch (Exception e)
                {
#if UNITY_EDITOR || UNITY_STANDALONE
                    DebugHelper.Assert(false, "Exception in Background Working Thread, Message:{0}, Callstack:\n{1}",
                        e.Message,
                        e.StackTrace
                        );
#endif
                }
            }

            WorkingList.Clear();

            Thread.Sleep(60);
        }
    }

    public void AddBackgroudOperation(BackgroudDelegate InDelegate)
    {
        lock (PendingWork)
        {
            PendingWork.Add(InDelegate);
        }
    }
}